4-Nitrobenzenesulfonyl chloride → HCID 722228, compound

Participants

Reaction Steps

Part A: To a stirred solution of D-valine (10.0 g) in a 2:1 mixture of THF/water (200 mL) containing triethylamine (3 equiv.) at 50° C. is added 4-nitrobenzene-sulfonyl chloride (0.9 equiv.) and the reaction is stirred at room temperature overnight. The resulting mixture is diluted with dichloromethane, and washed with 1N HCl, and water. The organic layer is dried over magnesium sulfate, filtered and concentrated in vacuo to provide the desired N-(nitrobenzenesulfonyl)-(D)-valine as a crude amino acid product. A solution of the crude amino acid (10 grams) in dry toluene (80 mL) is charged with dimethylformamide di-tertbutylacetal (45 mL) and heated to 100° C. for several hours. The resulting cooled solution is concentrated by rotary evaporation and purified by silica gel chromatography to provide the desired N-(4-nitrobenzenesulfonyl)-(D)-valine, tert-butyl ester.

Provenance & Evidence